Device for measuring workpieces such as screw threads and the like



May 26, 1953 w. RINKER 2,639,509

DEVICE FOR MEASURING WORKPIECES SUCH AS SCREW THREADS AND THE LIKE Filed June 2, 1950 2 Sheets-Sheet l May 26, 1953 w. RINKER 2,539,509

DEVICE FOR MEASURING WORKPIECES SUCH I AS SCREW THREADS AND THE LIKE Filed June 2, 1950 2 Sheets-Sheet 2 IN VEN TOR.

Patented May 26, 1953 DEVICE FOR MEASURING WORKPIECES SUCH AS SCREW THREADS AND THE LIKE Wilhelm Rinker, Wetzlar, Germany, assignor to Ernst Leitz, G. in. b. H., Wetzlar, Germany, a

corporation of Germany Application June 2, 1950, Serial No. 165,678 In Germany August 13, 1949 6 Claims.

The present invention relates to improvements in apparatus for measuring workpieces between measuring areas, and more particularly for measuring screw threads, etc., the device being adapted to operate in accordance with the so-called wire method of measuring, i. e., a method in-which use is made of measuring wires for measuring the threads.

This method allows the use of an ordinary micrometer, and measurement is accomplished by placing three wires, all of the same size into the groove of the thread. The size of the wires should be such that they will bear on the side walls of the thread at the pitch diameter when the thread is finished. Knowing the outside diameter of the screw, the wire sizes, and pitch of the thread, the measurement over the wires can then be computed by means of certain well-known formulae.

\As practiced heretofore, this method suffers from the drawback that the Weight of the screw which is being measured is apt to deform the measuring wires, particularly those of small diameter. Furthermore, the pressure exerted upon the lower measuring wire is greater than that exerted upon the upper wire due to the weight of the piece being measured, and this inequality detrimentally affects the accuracy of the operation. Last, but not least, it is very difficult to manually adjust the point of culmination of the piece to be measured with reference to the measuring means. It is ageneral object of the present invention to provide an apparatus of the character set forth, in which the measuring wires are not deformed during measurements, particularly when measuring threads of small pitch, and wherein no detrimental effect occurs by the unequal distribution of the weights on the upper and lower wires.

It is a further object of the present invention to provide means for exact measurement by supplying adjusting means not entirely dependent on hand operation, particularly in the adjustment of the apparatus to the point of culmination of the part to be measured.

In accordance with the above objects, the present invention provides a gimbal joint for mounting the test part supporting means as well as an adjustable balancing weight. The gimbal ring to which the test part support means is attached is preferably provided with positioning means 2 i prises a support arrangement for the test piece consisting of a yoke supported by gimbals com prising an exterior ring being provided with an arm having a sliding weight mounted on it, and an interior ring upon which the exterior ring is mounted and which is displaceable in the plane of both universal axes by means of an eccentric drive pin, as well as being pivotable about its own axis by means of a screw pin. The support arrangement is vertically adjustable and may be fastened to the pillar of the measuring stand by means of a sleeve movable along the-pillar and carrying the gimbals. The rings are suitably provided with pointers for indicating their deviations from the position of equilibrium. The holding yoke itself is suitably provided with adjustable holding points (centers).

. For a clearer understanding of the nature of this invention and the additional advantages, features and objects thereof, reference is made to the following description taken in connection with the accompanying drawings, in which like reference characters represent like or similar parts, and in which:

Figure 1 is an elevation showing the position of a test piece as measured by hand;

Figure 2 is an elevation of the measuring apparatus of this invention, with the holding arrangement, partly in section; I

Figure 3 is a top view of the holding arrangement, partly in section;

Figure 4 is an elevation, partly in section, showing the adjusting means for the universal rings on an enlarged scale.

As shown in the drawings, the apparatus consists of a standhaving a support or bed plate I and a guide pillar 2 along which the upper measuring head 4 is guided by means of arm 3. Member I carries the adjustable lower measuring base 5. Heretofore (see Fig. 1) measurements were taken by holding test piece a with one hand by means of a handle b, the measuring wires 0 being interposed between the measuring members & and 5. The present invention provides means including the sleeve 6 mounted on pillar 2 between plate I and the adjustable arm 3. The sleeve 6 is adjustable along the pillar 2 by means of the knurled nut I and may be tightened to said pillar by means of clamp arrangement 8. Inner ring 9 is pivotable around axle l0 mounted on sleeve 6; the ring 9 supports outer ring II which is pivotable about axle l2. The ring ll carries, on one side, balancing arm [3 with counterbalance Weight [4 displaceable on said arm 13, and on the other side said ring ll carries yoke l5 3 with its center points l6, which latter are adjustable in their axial directions, said center points being adapted to hold between them the piece a, Z) whose threads are to be measured. The inner ring Sis provided with cam H, which reaches into an eccentric groove 18 of disk I9, said disk being rotatably supported on sleeve 6 (Figs. 2 and 3). The ring 9 furthermore has associated with it a lever 20 which may be engaged or contacted by the adjusting screw 2! which latter is supported by sleeve 6. Opposite'the'adjusting screw and in axial direction, a springcontrolled compression member 22 is provided which also is fastened to sleeved: (Fi i 43),, Ring H is provided with two pointers 23, 24, which are 90 apart at its circumference, said pointers indicating the deviations of the universal hearing from the center position.

The measuring apparatus operates substantially as follows:

Fo th pur ose oi mea uring the pie ev atb s as e ed tw en su port-po nts Hiv o yoke 5, an the weig t o the p ece i bela d cor respon ine adjustment ofsl si hs i h l4v on the balancin arm =3.- .B rota in ish 19,- h adjustm nt o he axis o the p e lela-tiv to t e mea urin axis bet een u er nd lo r measurin supported s ac ompl sh d by m ans f urv d r ve l8 a d c m: ll- Th dju tment of ax s suppor ii, a, 5 oiithep e oi. b may b accom i hed: b ean o adjustin screw 2|. Theni asurine'w rese nterpos d betw en pie ea, b and th m a uri suppor 4 5 are now nly ubj ct t v the measurin load produced by the upper measurin 91.

It will be und rs oodthat the. ap aratus. escribed herein may be modified, numerous particularswitho t denartin 'irom thezspir t an scope or this invention as: defined theiol ow ing, claims.

Whatis claimedis:

- 1. In combination withadevicefor-measuring work pieces, such as screw threads and the like; by means of measuring wires positioned between a measuring base and a measuring head spaced from the base-in a vertical direction: a gimbal joint mounted between the measuring base and the measuring head and axially offset therefrom, said gimbal joint consistingofanormally hori: zontal interior ring. andla normally horizontal exterior ring mounted on the interiorring, sup-t port means for the work-- piece attached to said exterior ring and adapted to locate the wor k piece between the measuring base and the measuring head, an arm atached to the exterior ring substantially oppositely to the work piece supportmeans, and a weight slidably mounted on said arm and adapted to counterbalance the weight of the work piece.

2. In the combination defined in claim 1, means for adjusting the position of the interior ring.

3. The combination as defined in claim 2, wherein said adjusting means comprises a cam means for shifting the interior ring towards and away from said measuring base and measuring head.

4. A device formeasuring a work piece, such as a screw thread and the like, by means of measuring wires comprising, in combination, a horizontal support, a measuring base mounted on 58361 support, a measuring head vertically adjustably mounted on said support and vertically aligned with said base, a vertical support mounted on the horizontal support adjacent the measuring base, a vertically adjustable sleeve mounted on" said vertical support, a gimbal joint mounted on said sleeve between the measuring base and the measuring head, said gimbal joint consisting of. a, normally horizontal interior ring pivotally attached tothesleeve and a normally horizontal exterior ring mounted on the interior ring, support means for the work piece attached to said exterior ring and adapted tolocated. the work piece etw en he mea ur n ba e. and. the measuring head, an arm attached to thdexterior ring substantially oppositely to the workpiece uppo t m a a d a we g t sl de y mouhtedon said am a ap e o ount rb a ce; the ei ht o th o k p e e.-

A de ic as d fi edih claim i rth r com sin cam mcahs or hi tin hein eri ring towards and away rom said measuri g base a d measurin hea aid am mean c mprisin a is r ta eblymounted o sei s ee and ha in a r ve ccent ic wi h respe t o th ero the-int rio rin and a pin fixe l ettech d to said interior. ring and. e tend ng htosa dsroove- 6. A device as defined in. la m ,iur he com prisins'm ans for adjustin hehor zonta Position. of the pivotally moun d i te r ng,

R N E References. i ed nthe fil f is patent UNL ED STA ES Number Name Date- 791,364- Pfeifier May 30, 1905 2,105,961 Andreini Jan. 18, 1938 2,931,021 Bourdelais Nov. 18,194? 2,497,199 Aller Feb. 14 1950 2,563,910 Bean Aug. 14, 1951 FOREIGN PATENTS Number Country Date 341,360 Great Britain Jan. 15, 1931- 

